Book 1: Water

Book 2: Earth

Summary: After learning waterbending, Aang finds an earthbending teacher in Toph. In their travels, the group learns a secret that will give them the upper hand on the Fire Nation, but things do not go smoothly when they try to tell the Earth King about it. Meanwhile, Zuko becomes a fugitive from his nation, and his sister Azula joins the pursuit of the Avatar.

Book 3: Fire

Summary: The gaang prepares for the Day of Black Sun invasion. Things don't go as planned, and the group must come up with alternate ways of defeating the Fire Lord. Fortunately, they find a new unlikely ally -- or rather, a new unlikely ally finds them -- and a battle is fought to restore balance to the world.